1. Field of the Invention
The present invention relates to an intensive machine which can perform a plurality of processes in a series of steps of fabricating a multilayer substrate.
2. Description of the Related Art
Ceramic multilayer substrates are generally fabricated by a green sheet laminating. In the green sheet laminating, via holes for interlayer connection are formed in a plurality of ceramic green sheets by punching or the like, and thereafter, the via holes of each green sheet is filled with a conductive paste by printing and a wiring pattern is provided on an upper side of each ceramic green sheet by screen printing. Subsequently, these green sheets are integrated through lamination and thermocompression bonding, then being fired into a ceramic multilayer substrate.
Thus, in fabricating the ceramic multilayer substrate, at least the steps of forming via holes, filling and printing, printing wiring patterns need to be carried out. In a conventionally general fabrication line, however, a ceramic green sheet formed into the shape of a tape by the doctor blade method is cut into square pieces each having a predetermined size. Thereafter, the steps of forming via holes, filling and printing, printing wiring patterns are carried out. Accordingly, ceramic green sheets need to be positioned at each step and positions of the ceramic green sheets need to be detected at each step. As a result, processing apparatuses used at each fabrication step are complicated and large-sized, and a conveyor is required between the processing apparatuses of the fabrication steps. Consequently, the size and cost of the fabrication line is increased, and the processing apparatuses of the respective steps need to be set up.
In view of the foregoing problems, as shown in JP-A-2002-43748 gazette, a fabricating apparatus called “roll-to-roll” or “roll-to-sheet” has recently been proposed, in which apparatus a ceramic green sheet unwound from a roll has recently been conveyed to a via hole forming station without being cut, and after the via holes have been formed, the sheet is conveyed to a filling and printing station, where the via holes are filled with a conductive paste. Thereafter, a wiring pattern is printed. In the conventional “roll-to-roll” or “roll-to-sheet” system, the ceramic green sheet fed out of the roll is conveyed by a conveyer or take-up force of a take-up roll while being tensioned by tension rollers (see JP-A-4-2196 gazette).
In the foregoing conveying manners, however, a relative positional relation between each portion of the ceramic green sheet with respect to a conveying direction varies depending upon an amount of flexure of the ceramic green sheet due to the tension rollers. Accordingly, the ceramic green sheet needs to be positioned at each step and the position of the ceramic green sheet needs to be detected at each step. As a result, processing apparatuses used at each fabrication step are complicated, and the cost for each processing apparatus is increased. Moreover, the roller tension needs to be adjusted according to the thickness of and material for the ceramic green sheet. Additionally, since the mounting accuracy of each roller affects the accuracy in the feed of the ceramic green sheet, the number of assembling steps is increased.